In this study, following market penetration of PHEVs and EVs, the types of green car need to be supplied electricity externally, the efficient power charging infrastructure with a suggested charging monitoring system considering the smart grid system is proposed. PHEVs and EVs of green cars are used with electric supplied from Smart-Grid and stored in batteries. For the process, to establish stable and efficient connections between cars and the grids, the charging-monitoring system to manage electricity supply with communication information is required. The developed power supply system for charging automobiles are suitable for places such as 11 type or household usage. However, for the places required to charge simultaneously many vehicles, such as corporate or public parking lots, the system has problems causing installation cost increase while taking certain amount of spaces as well as inconvenient to manage for electricity suppliers. Therefore, in this study, we are proposed the efficient energy transformation method with the suggested charging monitoring system in grid, which has along with the description of charging process mechanism, the detail of control algorithm and the definition of function and interface between the relevant systems.